Re: [PATCH v2 4/4] virtio-net: Add support for USO features
On 26/07/2024 08.08, Michael S. Tsirkin wrote:
On Thu, Jul 25, 2024 at 06:18:20PM -0400, Peter Xu wrote:
> On Tue, Aug 01, 2023 at 01:31:48AM +0300, Yuri Benditovich wrote:
>> USO features of virtio-net device depend on kernel ability
>> to support them, for backward compatibility by default the
>> features are disabled on 8.0 and earlier.
>>
>> Signed-off-by: Yuri Benditovich <yuri.benditovich(a)daynix.com>
>> Signed-off-by: Andrew Melnychecnko <andrew(a)daynix.com>
>
> Looks like this patch broke migration when the VM starts on a host that has
> USO supported, to another host that doesn't..
This was always the case with all offloads. The answer at the moment is,
don't do this.
May I ask for my understanding:
"don't do this" = don't automatically enable/disable virtio features in
QEMU
depending on host kernel features, or "don't do this" = don't try to
migrate
between machines that have different host kernel features?
Long term, we need to start exposing management APIs
to discover this, and management has to disable unsupported features.
Ack, this likely needs some treatments from the libvirt side, too.
Thomas